[21.05] move backy to nixpkgs-23.05

[dhnasa]

removes nixpkgs-22.11
depends on flyingcircusio/backy#54
backy diff: https://github.com/flyingcircusio/backy/compare/5fa55f0c512e557bea3802f0be10e997e6f33f03..e37a7f6570b6b9194cb3a27d8db2951eb5c992ce

PL-131758, PL-131607
@flyingcircusio/release-managers

Release process

Impact: internal

Changelog:

• A number of bugfixes and improvements to our backup utility (backy)

  • consistency check improvements (automatic distrust on verification failures, improved lock handling, quarantining of inconsistent chunks)
  • fix service reload inconsistencies and crashes
  • remove outdated, unused code and features
  • fix a crash when parent pointers were incomplete and the immediate parent was missing its snapshot
  • Add nix flake support

Security implications

• Security requirements defined? (WHERE)
  • keep software up to date
• Security requirements tested? (EVIDENCE)
  • verify this builds and backups still work in dev environment
  • automated hydra tests still pass

[ctheune]

Looks good. I reviewed the actual release already.

[ctheune]

We just updated this to 2.5.1 to fix the "jobs" command. However, we found a weird inconsistency on the development backy server where backups where continuously failing with wrong data in the validation phase.

[ctheune]

I revisited this on patty and the only job that showed signs of failure is back to normal. My thought here is that we ended up in a weird situation after I used patty for different work-in-progress states and might have ended up confusing this one job.